This invention relates to a conveyor for advancing edgewise upstanding, mutually engaging stacked wafer-like articles by means of a vibratory trough conveyor assembly. An apparatus of this type is disclosed, for example, in Swiss Pat. No. 367,751. In this known construction, upstream of the vibratory trough conveyor these is arranged a conveyor belt and the conveyor trough, in turn, discharges the articles into a stationary channel from which the articles are removed in groups by a pusher (ejector) slide. A sensor, situated above the conveyor trough, interrupts the motion of the ejector slide in case the articles assume a pronounced oblique position (which is a result of an insufficient feed).
In the above-outlined known construction, the article stack is stationary in the vibrating conveyor trough when the ejector slide is in a de-energized state. This circumstance may lead to an abrasion of the edges of the articles--particularly if they are delicate confectionery items--and even may lead to a breakage thereof.
U.S. Pat. No. 4,462,522 discloses another conveyor apparatus of the above-outlined type. The construction described in this patent includes a plurality of side-by-side arranged vibratory troughs driven by a common crankshaft. The article advance is controlled by an energization and de-energization of the crankshaft drive. This arrangement causes an interruption of delivery of articles simultaneously in all the troughs. This is disadvangeous in case the different troughs deliver with different conveying rates which may occur, for example, in case an article accumulation is present only in one of the troughs.
German Offenlegungsschrift (published non-examined application) No. 2,243,906 discloses a sorting apparatus for wafer-like products, wherein the items are advanced by a conveyor belt formed of a plurality of parallel individual belts. To remove the pressure exerted by the articles against a barrier arranged at the downstream end of the conveyor belt, there is provided a rake which is pivotal about an axis oriented transversely to the direction of advance of the conveyor belt. The tines of the rake may be raised between the individual belts to thus brake the items at that location. Since this braking device is provided only locally, the remaining parts of the conveyor belt rub against the underside of the stationary items, leading to an undesired abrasion or to score marks.